Optical fiber buses are intended to replace electical buses in computers and communication switching systems. To fulfill this function, the optical fiber bus must allow for optical connections at very close intervals along the length of the bus. Because of the necessity for optical couplers (also referred to as taps) to be closely spaced along the optical fiber bus, two problems arise. The first problem is that optical couplers remove the higher order light modes from the bus so that downstream optical couplers receive only low order light modes which are not readily removed from the optical fiber bus for detection by optical couplers. Mode scramblers that redistribute the low order light modes to the high order light modes for the downstream optical couplers can solve this problem; however, these mode scramblers introduce the second problem of placing a large number of optical couplers and mode scramblers along a limited amount of optical fiber bus space at a reasonable cost.
The problem remaining in the prior art is the need for fabricating optical mode scramblers and optical couplers in a limited amount of optical fiber bus space using the same fabrication process.